1)

A colourless water-soluble solid A on heating gives equimolar quantities of B and C  . B gives dense white fumes with HCl and C does so with  NH3. B gives a brown precipitate with Nessler's reagent and C gives a white precipitate with nitrates of Ag+, Pb+ and Hg+. A is 


A) NH4Cl

B) NH4CO3

C) NH4NO2

D) FeSO4

Answer:

Option A

Explanation:

NH4Cl    NH3+HCl

A(colourless)                        B     & C ( equimolar quantities)

NH3+HClNH4Cl

 B                         dense white fumes

 NH3+2K2[HgI4]+3KOHH2NHgO.HgI+7KI+H2O

                Nessler's reagent                               Brown ppt. Iodine of Milinon's base

HCl+MNO3MCl+HNO3

  C                                 white ppt.

                                     (M= Ag+, Pb2+, Hg+)